Silica Refractories; Factors Affecting Their Quality and Methods of Testing the Raw Materials and Finished Ware (Paperback)

This historic book may have numerous typos and missing text. Purchasers can download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1919 Excerpt: ...more durable.brick than the 10mesh grind. However, all brick of this burn were too friable to be termed first class. The results of the later tests of this series are shown in Table 12. As is shown under burn No. 3, the 1 per cent of lime plus 1% per cent of Tennessee ball clay bricks expanded more than did the ones where lime alone was used, and the bricks which contained 2.5 per cent of Tennessee ball clay alone expanded less than the bricks that contained lime. TABLE 12.--Effects of Added Ingredients, Judged by Linear Expansion of Various Mixtures, Which Were Given Heat Treatments of Varying Duration and Temperature In the fourth burn mixes Nos. 3, 4, and 6 (Table 12) approached a common percentage expansion, while the expansion of mix No. 2 was considerably less. This seems to indicate that in this burn the materials reached approximately the limit of expansion, and that this limit was decreased in the case of No. 2 by the amount of transformation that had taken place in the calcining of the quartzite. Burn No. 5 shows a decided difference in expansion between the 8-mesh and 20-mesh material. The 20-mesh material after burning had no appreciable strength. This lot of brick, however, were made up somewhat drier than the 8-mesh brick. This may have had something to do with their friableness. The hard rock mix No. 9 shows a greater expansion than the soft rock tested. It yielded a brick which compared favorably with commercial brick as far as ring and spalling tendency are concerned. In the several tests above with loose-grained Medina quartzite, the exterior volume expansion did not exceed 6 per cent except with the most friable brick. Although several combinations gave fairly satisfactory brick, the most satisfactory probably being 8-mesh quartzite plus ...